sd-boot,sd-stub: also print version after the address

sd-boot,sd-stub: also print version after the address

The kernel, systemd, and many other things print their version during boot.
sd-boot and sd-stub are also important, so let's print the version if EFI_DEBUG.
(If !EFI_DEBUG, continue to be quiet.)

When updating the docs, I saw that that the text in HACKING.md was out of date.
Instead of trying to update the instructions there, make it shorter and refer
the reader to tools/debug-sd-boot.sh for details.